U.S. patent application number 12/529383 was filed with the patent office on 2010-04-15 for cooling arrangement for air or gas input in a vehicle.
Invention is credited to Zoltan Kardos, Erik Soderberg, Hans Wikstrom.
Application Number | 20100089088 12/529383 |
Document ID | / |
Family ID | 39759761 |
Filed Date | 2010-04-15 |
United States Patent
Application |
20100089088 |
Kind Code |
A1 |
Kardos; Zoltan ; et
al. |
April 15, 2010 |
COOLING ARRANGEMENT FOR AIR OR GAS INPUT IN A VEHICLE
Abstract
The present invention relates to a cooler arrangement in a
vehicle powered by a combustion engine. The cooler arrangement
comprises a first cooling element for cooling a first medium in the
form of a circulating coolant, and a radiator fan adapted to
generating an air flow through the first cooling element for
cooling the coolant when it circulates through the first cooling
element. The cooler arrangement comprises also a tubular casing
adapted to serving as a flow passage for the air which passes
through the first cooling element and at least one further cooling
element for cooling a second medium, which further cooling element
is arranged in the flow passage at a position downstream of the
first cooling element with respect to the intended direction of
flow of the cooling air through the flow passage.
Inventors: |
Kardos; Zoltan; (Sodertalje,
SE) ; Soderberg; Erik; (Stockholm, SE) ;
Wikstrom; Hans; (Johanneshov, SE) |
Correspondence
Address: |
OSTROLENK FABER GERB & SOFFEN
1180 AVENUE OF THE AMERICAS
NEW YORK
NY
100368403
US
|
Family ID: |
39759761 |
Appl. No.: |
12/529383 |
Filed: |
March 10, 2008 |
PCT Filed: |
March 10, 2008 |
PCT NO: |
PCT/SE08/50262 |
371 Date: |
September 1, 2009 |
Current U.S.
Class: |
62/323.1 ;
165/104.34; 62/401 |
Current CPC
Class: |
Y02T 10/12 20130101;
F02M 26/27 20160201; F02B 29/0431 20130101; F02M 26/05 20160201;
F01P 5/06 20130101; F01P 2003/187 20130101; B60K 11/04 20130101;
F02M 26/24 20160201; B60K 13/04 20130101; F02B 29/0475 20130101;
F01P 2060/02 20130101; F02B 29/0412 20130101; Y02T 10/146
20130101 |
Class at
Publication: |
62/323.1 ;
165/104.34; 62/401 |
International
Class: |
F25B 27/00 20060101
F25B027/00; F28D 15/00 20060101 F28D015/00; F25D 9/00 20060101
F25D009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 15, 2007 |
SE |
0700653-9 |
Claims
1. A cooler arrangement in a vehicle powered by combustion engine,
the cooler arrangement comprising a first cooling element for
cooling a first medium in the form of a circulating coolant, a
radiator fan configured and operable to generate an air flow
through the first cooling element for cooling the coolant when it
circulates through the first cooling element, a tubular casing
configured as a flow passage for air and positioned for passage of
air which has passed through the first cooling element; at least
one further cooling element for cooling a second medium, the
further cooling element being arranged in the flow passage at a
position downstream of the first cooling element with respect to an
intended direction of flow of the air through the flow passage, and
flow-limiting devices configured and operable to prevent air from
passing through the flow passage in selected situations.
2. A cooler arrangement according to claim 1, further comprising
the engine having an inlet line for air to the combustion engine
and an exhaust line for exhaust gases from the engine; the further
cooling element comprising an air-cooled EGR cooler configured and
operable for cooling recirculating exhaust gases and a connection
for then leading the recirculating exhaust gases from the EGR
cooler to the inlet line of the combustion engine.
3. A cooler arrangement according to claim 2, wherein the
air-cooled EGR cooler is located in the engine and is configured
and operable to subject the recirculating exhaust gases to a first
step of cooling, and, the cooler arrangement further comprising a
second EGR cooler configured and operable to subject the
recirculating exhaust gases to a second step of cooling and a
connection for leading the recirculating exhaust gases from the
first EGR cooler to the second EGR cooler.
4. A cooler arrangement according to claim 3, wherein the second
EGR cooler is situated upstream of the first cooling element with
respect to the intended direction of air flow through the first
cooling element.
5. A cooler arrangement according to claim 1, further comprising,
an air compressor for compressing air, and the further cooling
element comprises an air-cooled charge air cooler configured and
operable for cooling the compressed air and a connection for then
leading the cooled compressed air from the charge air cooler to the
inlet line of the combustion engine.
6. A cooler arrangement according to claim 5, wherein the
air-cooled charge air cooler is configured and operable for
subjecting the compressed air from the compressor to a first step
of cooling, and the cooler arrangement further comprises a second
air-cooled EGR cooler downstream of the charge air cooler in a flow
of compressed air, the second EGR cooler is configured and operable
for subjecting the compressed air to a second step of cooling.
7. A cooler arrangement according to claim 6, wherein the second
EGR cooler is situated upstream of the first cooling element with
respect to the intended direction of flow of the cooling air
through the first cooling element.
8. A cooler arrangement according to claim 1, wherein the tubular
casing is configured and operable to define a flow passage which
comprises an inlet aperture and one or more outlet apertures.
9. A cooler arrangement according to claim 1, wherein the
flow-limiting devices comprise a plurality of slatlike elements
arranged in parallel and being together pivotable between a
blocking position operable to prevent air from passing through the
flow passage and a non-blocking position operable to allow air to
pass through the flow passage.
10. A cooler arrangement according to claim 3, further comprising
an air compressor for compressing air, and another of the further
cooling elements which comprises an air-cooled charge air cooler
configured and operable for cooling of compressed air and a
connection for then leading the cooled compressed air from the
charge air cooler to the inlet line of the combustion engine.
11. A cooler arrangement according to claim 10, wherein the
air-cooled charge air cooler is configured and operable for
subjecting the compressed air from the compressor to a first step
of cooling, and the cooler arrangement further comprises a second
air-cooled EGR cooler downstream of the charge air cooler in a flow
of compressed air, the second EGR cooler is configured and operable
for subjecting the compressed air to a second step of cooling.
12. A cooler arrangement according to claim 3, wherein the tubular
casing is configured and operable to define a flow passage which
comprises an inlet aperture and one or more outlet apertures; the
first cooling element is toward the inlet aperture and the EGR
cooler is toward one of the outlet apertures.
13. A cooler arrangement according to claim 10, wherein the tubular
casing is configured and operable to define a flow passage which
comprises an inlet aperture and one or more outlet apertures; the
first cooling element is toward the inlet aperture and the charge
air cooler is toward one of the outlet apertures.
14. A cooler arrangement according to claim 8, wherein the first
cooling element is toward the inlet aperture and the further
cooling elements are toward the outlet aperture.
Description
BACKGROUND TO THE INVENTION AND STATE OF THE ART
[0001] The present invention relates to a cooler arrangement in a
vehicle according to the preamble of claim 1.
[0002] Particularly in heavy vehicles, the cooling system for
cooling the combustion engine is increasingly being used for
cooling other components and systems of the vehicle. If the cooling
system is too heavily loaded, however, there is risk of its not
coping satisfactorily with its main function of cooling the
combustion engine.
[0003] The technique called EGR (exhaust gas recirculation) is a
known way of leading part of the exhaust gases from a combustion
process in a combustion engine back, via a return line, to an inlet
line for supply of air to the combustion engine. A mixture of air
and exhaust gases is thus supplied via the inlet line to the
cylinders of the engine in which the combustion takes place. Adding
exhaust gases to the air causes a lower combustion temperature,
resulting inter alia in a reduced content of nitrogen oxides
NO.sub.x in the exhaust gases. This technique is used for both Otto
engines and diesel engines. However, the exhaust gases are at a
relatively high temperature and have therefore to be cooled before
they are led, together with the air, into the combustion spaces of
the combustion engine. Conventional EGR coolers use the coolant of
the vehicle's ordinary cooling system for cooling the recirculating
exhaust gases.
[0004] The air led to a combustion engine is usually compressed to
enable as large an amount of air as possible to be led into the
combustion engine. The air undergoes heating during the
compression. For an optimum amount of air to be supplied to the
combustion engine, the compressed air has therefore to be cooled
before it is led to the combustion engine. The compressed air is
usually cooled in a charge air cooler which has air at the
temperature of the surroundings flowing through it. The compressed
air can thus be cooled to a temperature only a few degrees above
the temperature of the surroundings. To achieve such cooling, the
charge air cooler is usually situated in front of the ordinary
radiator which cools the coolant. The coolant in the ordinary
cooling system therefore undergoes less effective cooling when it
is cooled by air which is at a higher temperature than the
surroundings. The capacity of the ordinary cooling system is thus
reduced when such a charge air cooler is used.
SUMMARY OF THE INVENTION
[0005] The object of the present invention is to provide a cooler
arrangement in a vehicle in which various components and systems
can be cooled effectively by substantially the same air as flows
through the radiator of the vehicle's ordinary cooling system,
without thereby appreciably impairing the capacity of the ordinary
cooling system.
[0006] This object is achieved with the arrangement of the kind
mentioned in the introduction which is characterised by the
features indicated in the characterising part of claim 1. Such a
tubular casing leads all the air which has passed through the first
cooling element to the further cooling element situated downstream.
The cooling effect undergone by the second medium in the further
cooling element depends on the temperature difference .DELTA.t
between the second medium and the cooling air which flows through
the further cooling element. If the second medium is at a high
temperature, the result is a relatively large temperature
difference even if the cooling air flow is at a somewhat higher
temperature than the temperature of the surroundings. Another
factor which affects the cooling effect is the amount of cooling
air which flows through the further cooling element per unit time.
The presence of the tubular casing thus ensures that the same large
air flow which passes through the first cooling element also passes
through the further cooling element. It is thus possible for there
to be both a relatively large temperature difference and a large
cooling air flow, resulting in good cooling of the second medium in
the further cooling element. The fact that the further cooling
element is situated downstream of the first cooling element does
not impair at all the cooling of the coolant in the first cooling
element and hence likewise does not impair the function of the
vehicle's ordinary cooling system.
[0007] According to a preferred embodiment of the present
invention, the further cooling element is an air-cooled EGR cooler
for cooling of recirculating exhaust gases which are led from an
exhaust line of the combustion engine to an inlet line for air to
the combustion engine. The exhaust gases from a combustion engine
are usually at a temperature of about 500-600.degree. C. The
temperature of the recirculating exhaust gases is so high that they
are cooled almost as effectively by air which is at a somewhat
raised temperature after it has passed through the first cooling
element as by air at the temperature of the surroundings. The
recirculating exhaust gases thus undergo effective cooling in said
EGR cooler situated within the tubular casing. With advantage, said
air-cooled EGR cooler is adapted to subjecting the returning
exhaust gases to a first step of cooling, and the cooler
arrangement comprises a second EGR cooler for subjecting the
returning exhaust gases to a second step of cooling. Although
effective cooling of the recirculating exhaust gases can be
effected in said EGR cooler, the exhaust gases cannot be cooled to
a temperature below the temperature of the cooling air flow within
the tubular casing. Since it is often desirable to cool the exhaust
gases to a temperature in the vicinity of the temperature of the
surroundings, it is advantageous to use a second EGR cooler for
subjecting the recirculating exhaust gases to a second step of
cooling. With advantage, the second EGR cooler is so situated that
it has air at the temperature of the surroundings flowing through
it. In that case the second EGR cooler may be situated upstream of
the first cooling element with respect to the intended direction of
air flow through the first cooling element. The cooling of the
coolant in the first cooling element is thereby somewhat impaired,
since the cooling air flow which cools the coolant in the first
cooling element will be at a somewhat raised temperature, but the
temperature rise of the cooling air flow is relatively moderate,
since the recirculating exhaust gases reaching the second EGR
cooler will not be at too high a temperature, having already
undergone the first step of cooling.
[0008] According to another embodiment of the invention, the
further cooling element is an air-cooled charge air cooler for
cooling of compressed air which is led to the combustion engine.
After the compression, the compressed air is at a high temperature.
The compressed air is therefore cooled almost as effectively by air
which is at a somewhat raised temperature as by air at the
temperature of the surroundings. The charge air thus undergoes
effective cooling in said charge air cooler situated within the
tubular casing. With advantage, said air-cooled charge air cooler
is adapted to subjecting the compressed air to a first step of
cooling and the cooler arrangement comprises a second charge air
cooler for subjecting the compressed air to a second step of
cooling. Although it may undergo effective cooling in said first
charge air cooler, the compressed air cannot be cooled to a
temperature below the temperature of the cooling air flow within
the tubular casing. Since it is often desirable to cool the exhaust
gases to a temperature in the vicinity of the temperature of the
surroundings, it is advantageous to use a second charge air cooler
for subjecting the compressed air to a second step of cooling. With
advantage, the second charge air cooler is so situated that it has
air at the temperature of the surroundings flowing through it. In
this case the second charge air cooler may be situated upstream of
the first cooling element with respect to the intended direction of
air flow through the first cooling element. The cooling of the
coolant in the first cooling element is thus somewhat impaired,
since the cooling air flow which cools the coolant in the first
cooling element will be at a somewhat raised temperature, but the
temperature rise of the cooling air flow is relatively moderate,
since the compressed air reaching the second charge air cooler will
not be at a relatively low temperature, having already undergone
the first step of cooling.
[0009] According to another preferred embodiment of the invention,
the tubular casing defines a flow passage which comprises an inlet
aperture and one or more outlet apertures. The inlet aperture may
be arranged close to the first cooling element to ensure that all
the air which passes through the first cooling element is led into
the flow passage defined by the tubular casing. Said further
cooling element is with advantage situated close to the outlet
aperture or apertures of the tubular casing. It is also possible
for a plurality of elements, e.g. an EGR cooler and a charge air
cooler, to be situated one after another in the tubular casing or
in parallel, e.g. close to an outlet aperture.
[0010] According to another preferred embodiment of the invention,
the cooler arrangement comprises flow-limiting means adapted to
preventing air from passing through the flow passage in particular
situations. The presence of such a flow passage inevitably results
in air being pushed through the flow passage against a certain
resistance. This usually leads to a vehicle with such a flow
passage being subject to a somewhat heightened air resistance
during operation. In certain operating states when the air flow
through the flow passage is not necessary, said flow-limiting
devices may be activated to block the air flow through the flow
passage. The result during operation of the vehicle is that the air
led towards a front portion of the vehicle will flow round the
vehicle, making it possible in many cases to reduce the vehicle's
air resistance and save fuel. Said flow-limiting devices may
comprise a plurality of slatlike elements arranged in parallel and
pivotable between a blocking position which prevents air from
passing through the flow passage and a non-blocking position which
allows air to pass through the flow passage. Such a louver-like
configuration is a relatively easy way of stopping/resuming the air
flow through the flow passage. Said flow-limiting devices may of
course be configured in some other way.
BRIEF DESCRIPTION OF THE DRAWING
[0011] A preferred embodiment of the invention is described below
by way of example with reference to the attached drawing in
which:
[0012] FIG. 1 depicts a cooler arrangement in a vehicle according
to an embodiment of the present invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
[0013] FIG. 1 depicts an arrangement for recirculation of the
exhaust gases of a supercharged combustion engine in a vehicle 1.
The combustion engine is here exemplified as a diesel engine 2.
Such recirculation is usually called EGR (exhaust gas
recirculation). Adding exhaust gases to the compressed air which is
led to the cylinders of the engine lowers the combustion
temperature and hence also the content of nitrogen oxides
(NO.sub.x) which are formed during the combustion processes. The
diesel engine 2 may be intended to power a heavy vehicle 1. The
exhaust gases from the cylinders of the diesel engine 2 are led via
an exhaust manifold 3 to an exhaust line 4. The exhaust gases in
the exhaust line 4, which are at above atmospheric pressure, are
led to a turbine 5. The turbine 5 is thus provided with driving
power which is transmitted via a connection to a compressor 6. The
compressor 6 thereupon compresses air which is led via an air
filter 7 into an inlet line 8. A first charge air cooler 9a and a
second charge air cooler 9b are arranged in the inlet line 8 to
subject the compressed air to two steps of cooling before it is led
to the diesel engine 2.
[0014] An arrangement for recirculation of part of the exhaust
gases in the exhaust line 4 comprises a return line 11 which
extends between the exhaust line 4 and the inlet line 8. The return
line 11 comprises a EGR valve 12 by which the exhaust flow in the
return line 11 can be shut off. The EGR valve 12 may also be used
for steplessly controlling the amount of exhaust gases which is led
from the exhaust line 4 to the inlet line 8 via the return line 11.
A control unit 13 is adapted to controlling the EGR valve 12 on the
basis of information about the current operating state of the
diesel engine 2. The control unit 13 may be a computer unit
provided with suitable software. The return line 11 comprises a
first EGR cooler 15a for subjecting the exhaust gases to a first
step of cooling and a second EGR cooler 15b for subjecting the
exhaust gases to a second step of cooling. In certain operating
states of supercharged diesel engines 2, the pressure of the
exhaust gases in the exhaust line 4 will be lower than the pressure
of the compressed air in the inlet line 8. In such operating
states, it is not possible to mix the exhaust gases in the return
line 11 with the compressed air in the inlet line 8 without special
auxiliary means. To this end it is possible to use, for example, a
venturi 16. If the combustion engine 2 is instead a supercharged
Otto engine, the exhaust gases in the return line 11 can be led
directly into the inlet line 8, since in substantially all
operating states of an Otto engine the exhaust gases in the exhaust
line 4 will be at a higher pressure than the compressed air in the
inlet line 8. When the exhaust gases have mixed with the compressed
air in the inlet line 8, the mixture is led via a manifold 17 to
the respective cylinders of the diesel engine 2. The diesel engine
2 is cooled in a conventional manner by a cooling system which
contains a circulating coolant. The coolant is cooled in a cooling
element 20 fitted close to a forward portion of the vehicle 1.
[0015] A radiator fan 10 is adapted to generating an air flow
through the cooling element 20 to cool the circulating coolant. The
radiator fan 10 is enclosed in a tubular casing 21 which serves as
a flow passage 22 for the air flow. The flow passage 22 has here an
inlet aperture 22a and two outlet apertures 22b, c. The cooling
element 20 is arranged close to the inlet aperture 22a. The first
charge air cooler 9a is arranged close to a first outlet aperture
22b. The first EGR cooler 15a is arranged close to a second outlet
aperture 22c. The second charge air cooler 9b is arranged in a
peripheral region A of the vehicle 1, which in this case is at a
front portion of the vehicle 1. The compressed air is thus cooled
in the second charge air cooler 9b by air which is at the
temperature of the surroundings. The second EGR cooler 15b is also
arranged in the peripheral region A of the vehicle 1. The returning
exhaust gases are thus cooled in the second EGR cooler 15b likewise
by air which is at the temperature of the surroundings. The second
charge air cooler 9b and the second EGR cooler 15b are arranged
upstream of the cooling element 20 with respect to the intended
direction of air flow.
[0016] A first flow-limiting device 23a is arranged in a portion of
the flow passage 22 in the vicinity of the first outlet aperture
22b, and a second flow-limiting device 23b is arranged in a portion
of the flow passage 22 in the vicinity of the second outlet
aperture 22b. The flow-limiting devices 23a, b, each comprise a
plurality of slatlike elements arranged in parallel and pivotable
between an open position in which they are substantially parallel
with the main direction of air flow and a blocking position in
which they are substantially perpendicular to the main direction of
air flow and thereby prevent air from flowing out through the
respective outlet apertures 22b, c. The control unit 13 is adapted
to regulating the flow-limiting devices 23a, b by means of
respective schematically depicted switching devices 24a, b.
[0017] During operation of the diesel engine 2, the exhaust gases
in the exhaust line 4 drive the turbine 5 before they are led out
to the surroundings. The turbine 5 is thereby provided with driving
power which drives the compressor 6. The compressor 6 compresses
air which is led via the air filter 7 into the inlet line 8. The
compression of the air also raises its temperature. The compressed
air is cooled first in the first charge air cooler 9a arranged
within the flow passage 22 close to the first outlet aperture 22b.
During operation of the diesel engine 2, the radiator fan 10, in
combination with the motion of the vehicle 1, generates an air flow
which passes initially through the second charge air cooler 9b, the
second EGR cooler 15b and the cooling element 20. The air is
thereafter led in through the inlet aperture 22a of the flow
passage 22. At this stage the air is at a raised temperature
relative to the surroundings, since it has been used for cooling
the media in the cooling elements 9b, 15b, 20 situated upstream,
but is usually at a definitely lower temperature than the
compressed air in the first charge air cooler 9a. Thus the
compressed air can be subjected to a first step of cooling by the
air which flows through the first charge air cooler 9a. The
compressed air is thereafter led to the second charge air cooler
9b, in which it is subjected to a second step of cooling by air at
the temperature of the surroundings, thereby cooling the compressed
air to a temperature only a few degrees above the temperature of
the surroundings.
[0018] In most operating states of the diesel engine 2, the control
unit 13 keeps the EGR valve 12 open so that part of the exhaust
gases in the exhaust line 4 is led into the return line 11. The
exhaust gases in the exhaust line 4 are usually at a temperature of
about 500-600.degree. C. when they reach the first EGR cooler 15a.
The first EGR cooler 15a is arranged within the tubular casing 21
close to the second outlet 22c. The cooling air flow here is thus
at a temperature which is higher than the surroundings but
definitely lower than the temperature of the exhaust gases in the
first EGR cooler 15a. This air flow can therefore be used for
subjecting the returned exhaust gases to a first step of cooling.
The returning exhaust gases can thus be subjected to a first step
of cooling to a temperature in the vicinity of the temperature of
this air, which may be in the range 70-90.degree. C. The exhaust
gases are thereafter led to the second EGR cooler 15b situated in
the peripheral region A of the vehicle alongside the second charge
air cooler 9b. The second EGR cooler 15b is thus assured of having
air at the temperature of the surroundings flowing through it. With
a suitably dimensioned second EGR cooler 15b the returned exhaust
gases can be cooled by the air flow to a temperature substantially
corresponding to the temperature of the surroundings. Exhaust gases
in the return line 11 can thus undergo cooling to substantially the
same temperature as the compressed air in the second charge air
cooler 9b. The mixture of the cooled exhaust gases and the
compressed air is thereafter led to the respective cylinders of the
diesel engine 2 via the inlet line 8 and the manifold 17.
[0019] Since both the recirculating exhaust gases and the
compressed air are at a relatively high temperature, they can be
cooled almost as effectively by air which is at a somewhat raised
temperature after it has passed through the first cooling element
20 as by air at the temperature of the surroundings. The compressed
air thus undergoes a first step of effective cooling in the first
charge air cooler 9a and the recirculating exhaust gases undergo a
first step of effective cooling in the first EGR cooler 15a. The
fact that the first charge air cooler 9a and the first EGR cooler
15a are situated downstream of the first cooling element 20 means
that the first step of cooling of the compressed air and the
exhaust gases has relatively little effect on the cooling of the
coolant in the first cooling element 20 and hence on the cooling of
the combustion engine 2. Since it is often desirable to cool the
compressed air and the recirculating exhaust gases to a temperature
in the vicinity of the temperature of the surroundings, it is
advantageous to use a second charge air cooler 9b and a second EGR
cooler 15b for subjecting the compressed air and the recirculating
exhaust gases to a second step of cooling. For practical reasons,
the second charge air cooler 9b and the second EGR cooler 15b are
here situated upstream of the first cooling element 20 with respect
to the intended direction of air flow through the first cooling
element. This inevitably somewhat impairs the cooling of the
coolant in the first cooling element 20, since the cooling air flow
which cools the coolant in the first cooling element 20 will
acquire a somewhat raised temperature, but the temperature rise of
the cooling air flow is relatively moderate, since the compressed
air reaching the second charge air cooler 9b and the recirculating
exhaust gases reaching the second EGR cooler 15b will not be at a
particularly high temperature, having already undergone a first
step of cooling.
[0020] In certain operating states in which there is no need for
the compressed air to be cooled in the first charge air cooler 9a
and/or no need for the recirculating exhaust gases to be cooled in
the first EGR cooler 15a, the control unit 13 may activate the
flow-limiting devices 23a, b. Air is prevented from flowing out
through the outlet apertures 22b, c so that the air flow through
the flow passage 22 is halted. The air which during operation of
the vehicle flows towards a front portion of the vehicle will
therefore flow round the vehicle, which in many cases may reduce
the vehicle's air resistance and save fuel. Said flow-limiting
devices comprise here louvre-like configurations with a plurality
of slatlike elements arranged in parallel and pivotable between a
blocking position which prevents air from passing through the flow
passage and a non-blocking position which allows air to pass
through the flow passage.
[0021] The invention is in no way limited to the embodiments
described with reference to the drawing but may be varied freely
within the scopes of the claims. The tubular casing 21 may, for
example, have any desired number of inlet apertures and outlet
apertures. Both an EGR cooler and a charge air cooler may be
arranged within the tubular casing close to one and the same outlet
aperture. The tubular casing 21 need not contain both an EGR cooler
and a charge air cooler but only one of said coolers.
* * * * *